U.S. patent application number 14/098347 was filed with the patent office on 2014-04-03 for adhesive film and method of encapsulating organic electronic device.
This patent application is currently assigned to LG CHEM, LTD.. The applicant listed for this patent is LG CHEM, LTD.. Invention is credited to Suk Ky CHANG, Yoon Gyung CHO, Seung Min LEE, Jung Sup SHIM, Hyun Jee YOO.
Application Number | 20140091296 14/098347 |
Document ID | / |
Family ID | 50384321 |
Filed Date | 2014-04-03 |
United States Patent
Application |
20140091296 |
Kind Code |
A1 |
YOO; Hyun Jee ; et
al. |
April 3, 2014 |
ADHESIVE FILM AND METHOD OF ENCAPSULATING ORGANIC ELECTRONIC
DEVICE
Abstract
Provided are an adhesive film, an encapsulated product of an
organic electronic device using the same, and a method of
encapsulating an organic electronic device. Particularly, the
adhesive film encapsulating the organic electronic device to cover
an entire surface of the organic electronic device includes an
adhesive layer including a curable resin and a moisture adsorbent.
The adhesive layer has a viscosity in a temperature range of 30 to
130.degree. C. of 10.sup.1 to 10.sup.6 Pas and a viscosity at room
temperature of 10.sup.6 Pas or more in an uncured state, and when
the adhesive layer has a multilayered structure, a difference in
melting viscosity between layers is less than 30 Pas. In addition,
the method of encapsulating an organic electronic device using the
adhesive film is provided.
Inventors: |
YOO; Hyun Jee; (Daejeon,
KR) ; CHO; Yoon Gyung; (Daejeon, KR) ; LEE;
Seung Min; (Daejeon, KR) ; CHANG; Suk Ky;
(Daejeon, KR) ; SHIM; Jung Sup; (Daejeon,
KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
LG CHEM, LTD. |
Seoul |
|
KR |
|
|
Assignee: |
LG CHEM, LTD.
Seoul
KR
|
Family ID: |
50384321 |
Appl. No.: |
14/098347 |
Filed: |
December 5, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/KR2012/009619 |
Nov 14, 2012 |
|
|
|
14098347 |
|
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Current U.S.
Class: |
257/40 ; 428/212;
438/99; 523/400; 523/457; 523/466 |
Current CPC
Class: |
C09J 2463/00 20130101;
C08K 3/32 20130101; C09J 2301/408 20200801; C08K 3/013 20180101;
C09J 2301/1242 20200801; C08K 2003/2227 20130101; H01L 51/524
20130101; C08K 3/22 20130101; H01L 51/5253 20130101; C09J 7/10
20180101; H01L 51/5259 20130101; Y10T 428/24942 20150115; C09J
11/00 20130101; C09J 7/35 20180101; H01L 51/5246 20130101; C09J
2203/326 20130101; C08K 3/24 20130101; C09J 2301/208 20200801; Y10T
428/24959 20150115 |
Class at
Publication: |
257/40 ; 523/400;
523/457; 523/466; 428/212; 438/99 |
International
Class: |
H01L 51/52 20060101
H01L051/52 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 14, 2011 |
KR |
10-2011-0118476 |
Nov 14, 2011 |
KR |
10-2011-0118478 |
Nov 14, 2012 |
KR |
10-2012-0128892 |
Nov 14, 2012 |
KR |
10-2012-0129018 |
Claims
1. An adhesive film encapsulating an organic electronic device,
comprising: an adhesive layer comprising a curable resin and a
moisture adsorbent, wherein the adhesive layer has a viscosity of
10.sup.1 to 10.sup.6 Pas at a temperature range from 30 to
130.degree. C., and a viscosity of 10.sup.6 Pas or more at room
temperature when the adhesive layer is in an uncured state.
2. The film of claim 1, wherein a degree of leaking an adhesive of
the adhesive layer is 1 mm or less from an original location when
the adhesive film is laminated to an adherent at a temperature
range from 50 to 100.degree. C. in an uncured state.
3. The film of claim 1, wherein the adhesive layer is composed of
at least two sub-adhesive layers, and a difference in viscosity
between the sub-adhesive layers at a temperature range from 30 to
130.degree. C. in an uncured state is less than 30 Pas.
4. The film of claim 3, wherein a difference in degree of leaking
an adhesive of the sub-adhesive layer is 0 to 300 .mu.m when the
adhesive film is laminated to an adherent at a temperature range
from 50 to 100.degree. C. in an uncured state.
5. The film of claim 3, wherein at least one sub-adhesive layer of
the sub-adhesive layers comprises a curable resin and a moisture
adsorbent.
6. The film of claim 1, wherein the curable resin has a water and
vapor transmission rate in a cured state of 20 g/m.sup.2day or
less.
7. The film of claim 1, wherein the curable resin is a heat-curable
or photocurable resin.
8. The film of claim 1, wherein the curable resin comprises at
least one curable functional group selected from a glycidyl group,
an isocyanate group, a hydroxyl group, a carboxyl group, an amide
group, an epoxide group, a cyclic ether group, a sulfide group, an
acetal group and a lactone group.
9. The film of claim 1, wherein the curable resin is an epoxy resin
comprising an aromatic group in a molecular structure.
10. The film of claim 1, wherein the moisture adsorbent is alumina,
metal oxide, metal salt or phosphorous pentoxide.
11. The film of claim 1, wherein the moisture adsorbent is at least
one selected from the group consisting of P.sub.2O.sub.5,
Li.sub.2O, Na.sub.2O, BaO, CaO, MgO, Li.sub.2SO.sub.4,
Na.sub.2SO.sub.4, CaSO.sub.4, MgSO.sub.4, CoSO.sub.4,
Ga.sub.2(SO.sub.4).sub.3, Ti(SO.sub.4).sub.2, NiSO.sub.4,
CaCl.sub.2, MgCl.sub.2, SrCl.sub.2, YCl.sub.3, CuCl.sub.2, CsF,
TaF.sub.5, NbF.sub.5, LiBr, CaBr.sub.2, CeBr.sub.3, SeBr.sub.4,
VBr.sub.3, MgBr.sub.2, BaI.sub.2, MgI.sub.2, Ba(ClO.sub.4).sub.2
and Mg(ClO.sub.4).sub.2.
12. The film of claim 1, wherein the adhesive layer comprises 5 to
100 parts by weight of a moisture adsorbent relative to 100 parts
by weight of the curable resin.
13. The film of claim 1, wherein the adhesive layer further
comprises a filler.
14. The film of claim 13, wherein the filler comprises at least one
selected from the group consisting of clay, talc, silica, barium
sulfate, aluminum hydroxide, calcium carbonate, magnesium
carbonate, zeolite, zirconia, titania or montmorillonite.
15. The film of claim 13, wherein the adhesive layer comprises 1 to
50 parts by weight of the filler relative to 100 parts by weight of
the curable resin.
16. The film of claim 1, wherein the adhesive layer further
comprises a curing agent.
17. The film of claim 16, wherein the curing agent is an
amine-based compound, an imidazole-based compound, a phenol-based
compound, a phosphorous-based compound or an acid anhydride-based
compound.
18. The film of claim 16, wherein the adhesive layer comprises 1 to
10 parts by weight of the curing agent relative to 100 parts by
weight of the curable resin.
19. The film of claim 1, wherein the adhesive layer further
comprises a high molecular weight resin.
20. An encapsulated product of an organic electronic device,
comprising: a substrate; an organic electronic device formed on the
substrate; and an adhesive film according to claim 1 encapsulating
the organic electronic device to cover an entire surface of the
organic electronic device.
21. The encapsulated product of claim 20, further comprising: a
second substrate on the adhesive film, wherein the adhesive film
adheres the substrate to the second substrate.
22. A method of encapsulating an organic electronic device,
comprising: applying the adhesive film according to claim 1 to a
substrate on which an organic electronic device is formed to cover
an entire surface of the organic electronic device with the
adhesive layer of the adhesive film; and curing the adhesive
layer.
23. The method of claim 22, wherein the application of the adhesive
film to the organic electronic device is performed by hot-roll
lamination, hot press or vacuum compression of the adhesive
film.
24. The method of claim 22, wherein the application of the adhesive
film to the organic electronic device is performed at 50 to
100.degree. C.
25. The method of claim 22, wherein the curing is performed by
heating at 70 to 110.degree. C., or radiating UV rays.
Description
FIELD
[0001] The present invention relates to an adhesive film and a
method of encapsulating an organic electronic device (OED) using
the same.
BACKGROUND
[0002] An organic electronic device refers to a device including an
organic material layer generating the exchange of charges using
holes and electrons, and may include a photovoltaic device, a
rectifier, a transmitter and an organic light-emitting diode
(OLED).
[0003] A representative organic electronic device, which is an
organic light-emitting diode (OLED), has less power consumption and
a higher response speed, and forms a thinner display device or
light than a conventional light source. In addition, the OLED has
excellent space utilization, and thus is expected to be applied in
various fields including all kinds of portable devices, monitors,
notebook computers and TVs.
[0004] To extend compatibility and use of the OLED, a major problem
to be solved in the related art is durability. Organic materials
and metal electrodes included in the OLED are very easily oxidized
by external factors such as moisture, and a product including the
OLED is very sensitive to environmental factors. Therefore, various
methods to effectively prevent penetration of oxygen or moisture
into the organic electronic device such as an OLED from an external
environment have been suggested.
[0005] Moreover, a more fundamental problem than durability is a
decrease in failure occurring due to degradation of laminating
properties during assembly of a panel. During the assembly of the
panel, it is very important that adhesive strength between panels
be maintained in a constant level, and the panels be laminated
without bubbles and maintain a uniform thickness.
[0006] Therefore, exemplary embodiments of the present invention
are to provide an encapsulant capable of corresponding to
manufacturing a larger and thinner organic electronic device,
providing structural advantages by encapsulating an organic
electronic device in a simpler process, and giving reliability from
an operation of assembling a panel.
SUMMARY
[0007] The present invention is directed to providing an adhesive
film, an encapsulated product of an organic electronic device using
the same, and a method of encapsulating an organic electronic
device.
[0008] In one aspect, the present invention provides an adhesive
film encapsulating an organic electronic device, including an
adhesive film including a curable resin and a water adsorbent. The
adhesive layer has a viscosity of 10.sup.1 to 10.sup.6 Pas at a
temperature range from 30 to 130.degree. C. in an uncured state,
and a viscosity of 10.sup.6 Pas or more at room temperature when
the adhesive layer is in an uncured state.
[0009] In another aspect, the present invention provides an
encapsulated product of an organic electronic device, including a
substrate, and an organic electronic device formed on the
substrate, and the adhesive film encapsulating the organic
electronic device to cover an entire surface thereof.
[0010] In still other aspect, the present invention provides a
method of encapsulating an organic electronic device, including
applying the adhesive film to a substrate on which an organic
electronic device is formed to cover an entire surface of the
organic electronic device with an adhesive layer of the adhesive
film; and curing the adhesive layer.
EFFECT
[0011] As an adhesive film according to exemplary embodiments of
the present invention controls viscosities at room temperature and
an increasing temperature of an adhesive layer in a B-stage state
in a specific range, excellent room temperature handability can be
obtained, an exact assembly margin cannot be ensured in the
assembly of a panel, an entire surface of the panel can be
maintained at a uniform thickness, an un-laminated part cannot be
made during lamination (increasing temperature lamination), and
failure rate can be reduced since the lamination does not occur
without bubbles. Moreover, as a film-type adhesive, not a
liquid-phase adhesive, is used, lifespan and durability of the
organic electronic device can be enhanced. In addition, the
adhesive film provides a structural advantage capable of supporting
and fixing upper and lower substrates of the organic electronic
device, thereby simplifying a method of encapsulating an organic
electronic device and cutting costs.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIGS. 1 to 3 are cross-sectional views of adhesive films
according to an exemplary embodiment of the present invention;
[0013] FIG. 4 is a cross-sectional view of an encapsulated product
of an organic electronic device according to an exemplary
embodiment of the present invention; and
[0014] FIGS. 5 to 7 are optical microscopic images observing
degrees of remaining bubbles after lamination when organic
light-emitting panels are formed using adhesive films according to
Example 1, and Comparative Examples 1 and 2.
DESCRIPTION OF REFERENCE NUMERALS
[0015] 21,23: base or release film [0016] 22: adhesive layer [0017]
31: substrate [0018] 32: adhesive film [0019] 33: organic
electronic device [0020] 34: second substrate (cover substrate)
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0021] An adhesive film according to an exemplary embodiment of the
present invention is used to encapsulate or capsulate an organic
electronic device. The term "organic electronic device (OED)" used
herein refers to a product or device having a structure including
an organic material layer generating the exchange of charges
between a pair of facing electrodes using holes and electrons. The
organic electronic device may include a photovoltaic device, a
rectifier, a transmitter and an OLED, but the present invention is
not limited thereto. In one embodiment, the organic electronic
device may be an OLED.
[0022] An adhesive film according to exemplary embodiments of the
present invention includes an adhesive layer, which is increased in
processibility by controlling viscosity at room temperature or an
increasing temperature of the adhesive layer in an uncured
(B-stage) state, and has a maximized moisture blocking effect by
including a moisture adsorbent.
[0023] In one embodiment, the adhesive layer may be formed using a
curable hot-melt-type adhesive composition including at least one
curable resin. The term "curable hot-melt-type adhesive
composition" used herein may refer to an adhesive maintaining a
solid or semi-solid state at room temperature, being melted by
applying heat to exhibit pressure-sensitive adhesive properties,
and tightly fixing a target material after the adhesive is
cured.
[0024] An adhesive film according to exemplary embodiments of the
present invention may have a viscosity of 10.sup.6 Pas or more, or
10.sup.7 Pas or more at room temperature in an uncured state. The
term "room temperature" refers to a temperature in a natural
environment, not increased or decreased. Room temperature may be
approximately 15.degree. C. to 35.degree. C., specifically,
approximately 20.degree. C. to 25.degree. C., and more
specifically, approximately 25.degree. C. The viscosity may be
measured using an advanced rheometric expansion system (ARES). When
the viscosity of the curable hot-melt-type adhesive is controlled
within the above range, a burr or crack is not generated during
punching, thereby easily handling the film, and the film has good
work processibility during the encapsulation of the organic
electronic device, thereby encapsulating a planar plate to a
uniform thickness in a planar type. In addition, as problems of
contraction and generation of a volatile gas occurring when the
resin is cured are considerably reduced, it (the film) can prevent
physical or chemical damage to the organic electronic device. As
long as the adhesive is maintained in a solid or semi-solid state,
the upper limit of the viscosity is not particularly limited, and
for example, in consideration of processibility, the viscosity may
be controlled in a range of approximately 10.sup.9 Pas or less.
[0025] The adhesive film according to exemplary embodiments of the
present invention may have a viscosity of 10.sup.1 to 10.sup.6 Pas
or 10.sup.2 to 10.sup.5 Pas during lamination, that is, in an
increasing temperature range before curing, in an uncured state.
The term "uncured state" used herein refers to an intermediate
state in which a curing reaction of a curable resin is rarely
performed, and is also called "B-stage." When the adhesive layer of
the adhesive film is laminated in an uncured state, the viscosity
in a range of increasing temperature of approximately 30 to
130.degree. C., which is an increasing temperature range before
curing, may be controlled within the above range, thereby reducing
failure and enhancing reliability during the assembly of a
panel.
[0026] Generally, to assemble a panel, thermal lamination is
performed in a vacuum state by applying heat of 50.degree. C. to
100.degree. C. However, when, in the lamination operation, bubbles
are captured or an un-laminated part is generated, a failure may be
generated. In addition, when an adhesive is leaked during the
thermal lamination due to a lower viscosity of the adhesive film
than a certain level, an exact assembly margin may not be provided,
and a uniform thickness may not be maintained in a large-scale
product. Contrarily, when the viscosity is higher than a certain
required level, it is possible to generate an un-laminated part in
the adhesive film. However, unlike the conventional art, the
adhesive film according to exemplary embodiments of the present
invention may prevent the generation or capture of bubbles, and
attach a panel without step difference by providing a tack
characteristic according to an increase in temperature of the
adhesive film during the attachment of the panel by controlling the
viscosity at increasing temperature within a specific range in an
uncured state. In addition, in a curing operation after attachment,
flowability of the adhesive film may be increased and wettability
may also be increased, thereby realizing better adhesive
characteristics and removing remaining fine bubbles.
[0027] In the assembly of a panel, the adhesive is flown or leaked
at a lamination temperature. When the adhesive film is laminated to
an adherent at a temperature range from 50.degree. C. to
100.degree. C. in an uncured state, the adhesive of the adhesive
layer may be leaked 1 mm or less from an original location. That
is, the adhesive present in any part of the adhesive layer in an
uncured state may not be flown or leaked more than 1 mm from an
original location during lamination. In such an uncured state, as
the flowability of the adhesive is controlled by controlling the
viscosity in an increasing temperature range of the adhesive layer,
reliability may be provided when the adhesive is applied to the
process.
[0028] The adhesive layer may be formed in a mono layer, or a
multilayered structure including at least two sub-adhesive layers.
When the adhesive film has a multilayered structure including at
least two sub-adhesive layers, a difference in viscosity at a
temperature range from 30.degree. C. to 130.degree. C. in the
uncured state between the sub-adhesive layers may be less than 30
Pas, 25 Pas or less or 20 Pas or less. In the sub-adhesive layers,
the viscosity of an upper or lower layer may be high or low, and
the difference in viscosity between the sub-adhesive layers may be
preferably 0 Pas.
[0029] In addition, when the difference in viscosity at 30.degree.
C. to 130.degree. C. in the uncured state between the sub-adhesive
layers is less than 30 Pas, a difference in flowability or leakage
between the sub-adhesive layers in the lamination may be 0 .mu.m to
300 .mu.m. Here, in a general lamination operation, the adhesive
film may be thermally laminated on an adherent at a temperature
range from 50.degree. C. to 100.degree. C. and a variable pressure
range, but the present invention is not limited thereto. As an
embodiment, the lamination may be performed at a pressure of 0.05
MPa to 5 MPa.
[0030] The viscosity of each sub-adhesive layer may be controlled
by changing components included in the adhesive layer, or changing
a content ratio of the components, a content of an additive, the
kind or diameter of a moisture adsorbent or filler, and a condition
for forming an adhesive film.
[0031] When the adhesive layer includes at least two sub-adhesive
layers, at least one sub-adhesive layer may include a curable resin
and a moisture adherent. For example, when the adhesive layer is
formed with two layers, a moisture adsorbent may be included in an
upper adhesive layer, not in a lower adhesive layer. In this case,
when the adhesive layer will be used to assemble a panel, a
moisture adsorbent may not be included in a part directly attached
to an organic electronic device, and thus damage to a device due to
a moisture adsorbent may be prevented.
[0032] In the sub-adhesive layers constituting the adhesive layer,
a curable resin, the kind and content of a moisture adsorbent or
another additive, and the kind and content of a filler may be the
same as or different from each other.
[0033] The curable resin may have a water vapor transmission rate
(WVTR) in a cured state of 50 g/m.sup.2day or less, 30 g/m.sup.2day
or less, 20 g/m.sup.2day or less, or 15 g/m.sup.2day or less. The
term "cured state of a curable resin" refers to a state converted
into a state in which the curable resin has constant components of
the moisture adsorbent and filler and serves as a structural
adhesive when the curable resin is cured or crosslinked by being
used alone or a reaction with other components such as a curing
agent and then applied to an encapsulant, through the radiation of
heat or light. The WVTR may be measured in a thickness direction of
the cured product at 38.degree. C. and under a relative humidity of
100% after the curable resin is cured and the cured product is
formed in a film having a thickness of 80 .mu.m. In addition, the
WVTR may be measured according to ASTM F1249.
[0034] As the WVTR of the curable resin is controlled within the
above range, the penetration of water, vapor or oxygen into an
encapsulated product of an organic electronic device may be
effectively inhibited, and an effect of inducing a moisture
reactive adsorbent may be exhibited.
[0035] As the WVTR in the cured state of the resin is decreased,
the encapsulated structure has better performance. The lower limit
of the WVTR is not particularly limited, but may be preferably 0
g/m.sup.2day.
[0036] The adhesive film may have a glass transition temperature
(Tg) in the cured state of 90.degree. C. or more.
[0037] A specific kind of curable resin capable of being used in
exemplary embodiments of the present invention is not particularly
limited, and for example, may include various heat-curable,
photocurable and dual curable resins, which are known in the
related art. The term "heat-curable resin" refers to a resin
capable of being cured through application of suitable heat or an
aging process, the term "photocurable resin" refers to a resin
capable of being cured by the radiation of an electromagnetic wave,
and the term "dual curable resin" refers to a resin simultaneously
having characteristics of a heat-curable resin and a photocurable
resin and capable of being cured by radiation of an electromagnetic
wave and application of heat. In addition, in the category of the
electromagnetic waves, particle beams such as microwaves, IR rays,
UV rays, X rays and gamma rays, and electron beams such as
alpha-particle beams, proton beams, neutron beams and electron
beams may be included. As an embodiment of the photocurable resin,
a cationic photocurable resin may be used. The cationic
photocurable resin refers to a resin capable of being cured by
cationic polymerization or a cationic curing reaction induced by
the radiation of an electromagnetic wave.
[0038] A specific kind of curable resin capable of being used in
exemplary embodiments of the present invention is not particularly
limited, as long as the curable resin has the above-described
characteristics. For example, a resin capable of being cured to
exhibit adhesive characteristics may include a resin including at
least one heat-curable functional group of a glycidyl group, an
isocyanate group, a hydroxyl group, a carboxyl group or an amide
group, or at least one functional group capable of being cured by
the radiation of an electromagnetic wave, selected from an epoxide
group, a cyclic ether group, a sulfide group, an acetal group and a
lactone group. In addition, a specific kind of resin may include an
acryl resin, a polyether resin, an isocyanate resin or an epoxy
resin, but the present invention is not limited thereto.
[0039] As the curable resin, an aromatic or aliphatic, or linear or
branched epoxy resin may be used. In one exemplary embodiment of
the present invention, an epoxy resin containing at least two
functional groups and an epoxy equivalent of 180 to 1,000 g/eq may
be used. When the epoxy resin having the above epoxy equivalent is
used, the cured product may have effectively-maintained
characteristics such as adhesive performance and a glass transition
temperature. Such an epoxy resin may be one or a mixture of at
least two of a cresol novolac epoxy resin, a bisphenol A-type epoxy
resin, a bisphenol A-type novolac epoxy resin, a phenol novolac
epoxy resin, a 4-functional epoxy resin, a biphenyl-type epoxy
resin, a triphenolmethane-type epoxy resin, an alkyl-modified
triphenolmethane epoxy resin, a naphthalene-type epoxy resin, a
dicyclopentadiene-type epoxy resin and a dicyclopentadiene-modified
phenol-type epoxy resin.
[0040] In specific exemplary embodiments of the present invention,
an epoxy resin including a ring structure in a molecular structure
may be used, and for example, an epoxy resin including an aromatic
group (e.g., a phenyl group) may be used. When the epoxy resin
includes an aromatic group, a cured product may have excellent
thermal and chemical stabilites and low moisture absorption,
thereby enhancing reliability of the encapsulated product of an
organic electronic device. The aromatic-group containing epoxy
resin may be, but is not limited to, one or a mixture of at least
two of a biphenyl-type epoxy resin, a dicyclopentadiene-type epoxy
resin, a naphthalene-type epoxy resin, a dicyclopentadiene-modified
phenol-type epoxy resin, a cresol-based epoxy resin, a
bisphenol-based epoxy resin, a xyloc-based epoxy resin, a
multifunctional epoxy resin, a phenol novolac epoxy resin, a
triphenolmethane-type epoxy resin and an alkyl-modified
triphenolmethane epoxy resin.
[0041] The adhesive layer (in the case of a mono layer, an adhesive
layer, or in the case of a multilayer, a part or all of at least
one sub-adhesive layer) includes a moisture adsorbent in addition
to the curable resin. The term "moisture adsorbent" may be used as
a meaning including components capable of adsorbing or removing
water or vapor entering from an external environment, through a
chemical reaction with moisture, and also called a
moisture-reactive adsorbent.
[0042] The moisture adsorbent adsorbs water or vapor by a chemical
reaction with vapor, water or oxygen entering the adhesive layer. A
specific kind of moisture adsorbent capable of being used in
exemplary embodiments of the present invention is not particularly
limited, and for example, may be one or a mixture of at least two
of metal powder such as alumina, a metal oxide, an organic metal
oxide, a metal salt and phosphorous pentoxide (P.sub.2O.sub.5).
[0043] A specific embodiment of the metal oxide may be lithium
oxide (Li.sub.2O), sodium oxide (Na.sub.2O), barium oxide (BaO),
calcium oxide (CaO) or magnesium oxide (MgO), the metal salt may be
a sulfate such as lithium sulfate (Li.sub.2SO.sub.4), sodium
sulfate (Na.sub.2SO.sub.4), calcium sulfate (CaSO.sub.4), magnesium
sulfate (MgSO.sub.4), cobalt sulfate (CoSO.sub.4), gallium sulfate
(Ga.sub.2(SO.sub.4).sub.3), titanium sulfate (Ti(SO.sub.4).sub.2)
or nickel sulfate (NiSO.sub.4); a metal halide such as calcium
chloride (CaCl.sub.2), magnesium chloride (MgCl.sub.2), strontium
chloride (SrCl.sub.2), yttrium chloride (YCl.sub.3), copper
chloride (CuCl.sub.2), cesium fluoride (CsF), tantalum fluoride
(TaF.sub.5), niobium fluoride (NbF.sub.5), lithium bromide (LiBr),
calcium bromide (CaBr.sub.2), cesium bromide (CeBr.sub.3), selenium
bromide (SeBr.sub.4), vanadium bromide (VBr.sub.3), magnesium
bromide (MgBr.sub.2), barium iodide (BaI.sub.2) or magnesium iodide
(MgI.sub.2); or a metal chlorate such as barium perchlorate
(Ba(ClO.sub.4).sub.2) or magnesium perchlorate
(Mg(ClO.sub.4).sub.2), but the present invention is not limited
thereto.
[0044] In exemplary embodiments of the present invention, the metal
oxides may be mixed with the composition in a state in which the
moisture adsorbent is suitably processed. For example, depending on
the kind of organic electronic device to which the adhesive film is
to be applied, the adhesive layer may be a thin film having a
thickness of 30 .mu.m or less, and in this case, it may be
necessary to perform a grinding process to the moisture adsorbent.
To grind the moisture adsorbent, a process such as a 3-roll mill,
bead mill or ball mill may be used. In addition, when the adhesive
film is applied to a top-emission type organic electronic device,
transmissivity of the adhesive layer is very important, and thus it
is necessary to decrease the size of the moisture adsorbent.
Therefore, to be used in such a use, the moisture adsorbent is
necessarily subjected to a grinding process.
[0045] The adhesive layer may include the moisture adsorbent at 5
to 100 or 5 to 90 parts by weight relative to 100 parts by weight
of the curable resin. As the content of the moisture adsorbent is
controlled within the above range, a moisture blocking property may
be maximized within a range causing no damage to the organic
electronic device.
[0046] Unless particularly defined otherwise, the unit "parts by
weight" used herein refers to a weight ratio between
components.
[0047] In the adhesive layer of the adhesive film, the moisture
adsorbent may be uniformly dispersed.
[0048] The adhesive layer of the adhesive film according to
exemplary embodiments of the present invention may include a
filler, for example, an inorganic filler. The filler may extend a
traveling path of water or vapor penetrated into an encapsulated
structure to inhibit the penetration of water or vapor, and
maximize a blocking property to water and vapor due to a matrix
structure of a curable resin and through interaction with the
moisture adsorbent. A specific kind of filler capable of being used
in exemplary embodiments of the present invention may be, but is
not limited to, one or a mixture of at least two of clay, talc,
silica, barium sulfate, aluminum hydroxide, calcium carbonate,
magnesium carbonate, zeolite, zirconia, titania or
montmorillonite.
[0049] In addition, to increase binding efficiency between the
filler and the curable resin, a product whose surface is treated
with an organic material may be used as the filler, or a coupling
agent may be further added to the filler.
[0050] The adhesive composition may include 1 to 50 or 1 to 30
parts by weight of the filler relative to 100 parts by weight of
the curable resin. As the content of the filler is controlled to 1
part by weight or more, a cured product having excellent water or
vapor blocking properties and mechanical properties may be
provided. In addition, as the content of the filler is controlled
to 50 parts by weight or less, a cured product capable of being
formed in a film type, and exhibiting adhesive characteristics even
when being formed in a thin film, may be provided.
[0051] The adhesive layer of the adhesive film according to
exemplary embodiments of the present invention may further include
an initiator capable of initiating a curing reaction of a curing
agent or resin capable of forming a matrix such as a crosslinking
structure by a reaction with a curable resin, for example, a
cationic photopolymerization initiator.
[0052] A specific kind of curing agent is not particularly limited,
and may be suitably selected according to the kind of functional
group included in a curable resin or resin used. The curing agent
may be a potential curing agent such as an imidazole-based
compound. For example, when the epoxy resin is used as a curable
resin, a general curing agent for an epoxy resin known in the
related art may be used as the curing agent, which may be, but is
not limited to, one or a mixture of at least two of all kinds of
amine-based compounds, imidazole-based compounds, phenol-based
compounds, phosphorous-based compounds and acid anhydride-based
compounds.
[0053] The adhesive layer may include the curing agent at 1 to 20
or 1 to 10 parts by weight relative to 100 parts by weight of the
curable resin. However, the content is only an example of the
present invention. That is, the content of the curing agent may be
changed according to the kind and content of the curing agent or
functional group, and a matrix structure or crosslinking density to
be realized.
[0054] In addition, the kind of initiator, for example, the
cationic photopolymerization initiator is not particularly limited,
and thus a known cationic photopolymerization initiator such as an
aromatic diazonium salt, an aromatic iodine aluminum salt, an
aromatic sulfonium salt or an iron-arene complex, and preferably,
an aromatic sulfonium salt, may be used. However, the present
invention is not limited thereto.
[0055] For example, the initiator may be included at 0.01 to 10 or
0.1 to 3 parts by weight relative to 100 parts by weight of the
curable resin. When the content of the cationic photopolymerization
initiator is excessively low, curing may not be sufficiently
performed, and when the content of the cationic photopolymerization
initiator is excessively high, the content of the ionic material is
increased after curing, thereby degrading durability of an
adhesive, or because of the initiator having a characteristic of
forming a conjugate acid, the optical durability of the film may be
degraded. Depending on a base, corrosion may occur, and in
consideration of this, a suitable content range may be
selected.
[0056] The adhesive layer may further include a high molecular
weight resin. The high molecular weight resin may serve to improve
moldability when a composition for forming an adhesive layer is
molded in a film or sheet. In addition, the high molecular weight
resin may serve as a high-temperature viscosity controller for
controlling flowability during a hot-melting process.
[0057] The kind of high molecular weight resin capable of being
used in exemplary embodiments of the present invention is not
particularly limited as long as the resin has compatibility with
another component such as the curable resin. A specific kind of
high molecular weight resin capable of being used may be, but is
not limited to, a resin having a weight average molecular weight of
20,000 or more, which is one or a mixture of at least two of a
phenoxy resin, an acrylate resin, a high molecular weight epoxy
resin, a ultra-high molecular weight epoxy resin, a rubber
containing a high polarity functional group, and a reactive rubber
containing a high polarity functional group, but the present
invention is not limited thereto.
[0058] When a high molecular weight resin is included in the
adhesive layer, the content is controlled according to a desired
physical property, not particularly limited. For example, the high
molecular weight resin may be included at approximately 10 to 200,
20 to 150, or 20 to 100 parts by weight or less relative to 100
parts by weight of the curable resin. As the content of a binder
resin is controlled to 10 to 200 parts by weight or less, the
compatibility with each component of the resin composition may be
effectively maintained, and the binder resin may serve as an
adhesive. When the content of the high molecular weight resin, that
is, the binder resin, is excessively low, the resin may be leaked
outside due to a low viscosity in a lamination process, thereby
increasing room temperature pressure-sensitive adhesive strength
and having a difficulty in controlling releasability. In addition,
when the content of the high molecular weight resin is excessively
high, failure in lamination property may be generated. Therefore,
as the viscosity of each layer is controlled by controlling the
content of the high molecular weight resin to reduce a difference
in viscosity, optimized processibility and physical properties may
be ensured.
[0059] The adhesive layer of the adhesive film may further include
additives such as an additional filler to improve durability of the
cured product, a coupling agent for enhancing mechanical strength
and adhesive strength, a plasticizer, a UV stabilizer and an
antioxidant without an influence on the effects of the present
invention.
[0060] A structure of the adhesive film according to exemplary
embodiments of the present invention is not particularly limited if
the film includes the adhesive layer. For example, the adhesive
film may have a structure including a base or release film
(hereinafter, referred to as a "first film"); and adhesive layer
formed on the base or release film. The adhesive film may further
include another base or release film (hereinafter, referred to as a
"second film"), which is formed on the adhesive layer.
[0061] FIGS. 1 to 3 are cross-sectional views of an adhesive film
according to an exemplary of the present invention. As shown in
FIG. 1, an adhesive film according to exemplary embodiments of the
present invention may include an adhesive layer 22 formed on a base
or release film 21.
[0062] In another aspect of the present invention, as shown in FIG.
2, the adhesive film may include an adhesive layer having a
multilayered structure, for example, including a first sub-adhesive
layer 22a excluding a moisture adsorbent, and a second adhesive
layer 22b including a moisture adsorbent, which are sequentially
formed on the base or release film 21.
[0063] In still another aspect of the present invention, as shown
in FIG. 3, the adhesive film may further include a base or release
film 23 formed on the adhesive layer 22. In one embodiment, to
realize a flexible display, a gas barrier layer may be disposed on
one surface of the base film. However, the adhesive film shown in
the drawings is merely an aspect of the present invention. The
adhesive film according to exemplary embodiments of the present
invention may include, for example, a composition of the present
invention without a support base, and may have a type in which a
monolayered adhesive layer maintaining a solid or semi-solid phase
at room temperature, and in some cases, a type of a double-sided
adhesive film.
[0064] A specific kind of first film capable of being used in
exemplary embodiments of the present invention is not particularly
limited. As the first film, for example, a general polymer film in
the related art may be used. For example, as the base or release
film, a polyethyleneterephthalate film, a polytetrafluorethylene
film, a polyethylene film, a polypropylene film, a polybutene film,
a polybutadiene film, a vinylchloride copolymer film, a
polyurethane film, ethylene-a vinylacetate film, an
ethylene-propylene copolymer film, an ethylene-acrylic acid ethyl
copolymer film, an ethylene-acrylic acid methyl copolymer film or a
polyimide film, may be used. In addition, suitable releasing
treatment may be performed to one or both surfaces of the base or
release film. As a releasing agent used in releasing treatment of
the base film, an alkyd-based, silicon-based, fluorine-based,
unsaturated ester-based, polyolefin-based or wax-based releasing
agent, and preferably, for thermal resistance, an alkyd-based,
silicon-based or fluorine-based releasing agent may be used, but
the present invention is not limited thereto.
[0065] In addition, the kind of second film (hereinafter, also
referred to as a "cover film") capable of being used in exemplary
embodiments of the present invention is neither particularly
limited. For example, the second film may be the same as or
different from the first film within the range exemplified as the
first film. In addition, the second film may also be subjected to
suitable releasing treatment.
[0066] A thickness of the base or release film (first film) is not
particularly limited, and may be suitably selected according to its
use. For example, the first film may have a thickness of 10 .mu.m
to 500 .mu.m or 20 .mu.m to 200 .mu.m. When the thickness of the
film is less than 10 .mu.m, transformation of the base film may
easily occur in the forming process, and when the thickness of the
film is more than 500 .mu.m, economic feasibility may be
decreased.
[0067] A thickness of the second film may neither be particularly
limited. For example, the thickness of the second film may be set
the same as that of the first film. Alternatively, in consideration
of processibility, the thickness of the second film may be set
relatively smaller than that of the first film.
[0068] A thickness of the adhesive layer included in the adhesive
film according to exemplary embodiments of the present invention is
not particularly limited, and may be suitably selected according to
the following condition in consideration of the use of the film.
The adhesive layer may be, for example, 5 .mu.m to 200 .mu.m or 5
.mu.m to 100 .mu.m.
[0069] In exemplary embodiments of the present invention, a method
of forming the adhesive film is not particularly limited. For
example, the adhesive film may be formed by a method including
coating a coating solution including a composition for an adhesive
layer on a base or release film (first operation), and drying the
coating solution coated in the first operation (second operation).
The method of forming the adhesive film may further include further
compressing a base or release film on the coating solution dried in
the second operation (third operation).
[0070] The first operation is to prepare a coating solution by
dissolving or dispersing the composition for the adhesive layer in
a suitable solvent. The content of the curable resin included in
the coating solution used in the operation may be suitably
controlled according to desired moisture blocking properties and
film moldability.
[0071] The kind of the solvent used in the preparation of the
coating solution is not particularly limited. However, since drying
time of the solvent is excessively long, or the solvent is
necessarily dried at high temperature, problems may arise in terms
of workability or durability of the adhesive film. For this reason,
a solvent having a volatilization temperature of 100.degree. C. or
less may be used. Moreover, in consideration of film moldability, a
small amount of the solvent having a volatilization temperature
within the above range or more may be mixed. The solvent may be,
but is not limited to, one or a mixture of at least two of
methylethylketone (MEK), acetone, toluene, dimethylformamide (DMF),
methylcellosolve (MCS), tetrahydrofuran (THF) or
N-methylpyrollidone (NMP).
[0072] In the first operation, a method of coating the coating
solution on a base or release film is not particularly limited, and
a known method such as knife coating, roll coating, spray coating,
gravure coating, curtain coating, comma coating or lip coating, may
be used without limitation.
[0073] The second operation is to form an adhesive layer by drying
the coating solution coated in the first operation. That is, in the
second operation, an adhesive layer may be formed by drying and
removing a solvent by heating the coating solution coated to the
film. Here, a drying condition is not particularly limited, and the
drying may be performed at 70.degree. C. to 200.degree. C. for 1
minutes to 10 minutes.
[0074] In the forming method, after the second operation, a third
operation of compressing an additional base or release film on the
adhesive layer formed on the film, may be further performed. In the
third operation, the additional release or base film (cover film or
second film) may be compressed on the dried adhesive layer coated
on the film by a roll lamination process.
[0075] FIG. 4 is a cross-sectional view of an encapsulated product
of an organic electronic device according to an exemplary
embodiment of the present invention. In another exemplary
embodiment of the present invention, an encapsulated product of an
organic electronic device includes a substrate 31; an organic
electronic device 33 formed on the substrate 31, and the
above-described adhesive film 32 encapsulating the organic
electronic device 33 to cover an entire surface of the organic
electronic device 33. Here, the covering of the entire surface of
the organic electronic device 33 refers to attachment of the
adhesive film 32 to an entire area (all surfaces, for example,
upper and side surfaces, not in contact with the substrate) of the
organic electronic device 33 without a gap.
[0076] The encapsulated product of the organic electronic device
may further include a second substrate (cover substrate) 34 on the
adhesive film 32, which serves to attach the substrate 31 with the
second substrate 34.
[0077] The organic electronic device 33 may be, for example, an
organic light-emitting diode (OLED).
[0078] The encapsulated product of the organic electronic device
may include a protective layer (not shown) protecting the organic
electronic device 33 between the adhesive film 32 and the organic
electronic device 33.
[0079] The encapsulated product of the organic electronic device
according to exemplary embodiments of the present invention has
advantages of a simple process and a decrease in production cost.
The encapsulated product of the organic electronic device can also
be used regardless of a method of designing the organic electronic
device, and provide excellent mechanical durability to the organic
electronic device.
[0080] In still another exemplary embodiment of the present
invention, a method of encapsulating an organic electronic device
includes applying an adhesive layer of the above-described adhesive
film to a substrate on which an organic electronic device is formed
to cover an entire surface of the organic electronic device, and
curing the adhesive layer.
[0081] The application of the adhesive film to the organic
electronic device may be performed by hot-roll lamination, hot
press or vacuum compression of the adhesive film, but the present
invention is not particularly limited.
[0082] The application of the adhesive film to the organic
electronic device may be performed at 50.degree. C. to 100.degree.
C., and the curing operation may be performed by heating in a range
of 70.degree. C. to 110.degree. C., or radiating a UV ray.
[0083] In addition, the method may further include attaching the
adhesive film to an additional encapsulation material such as glass
or metal to face each other.
[0084] The method of encapsulating an organic electronic device
includes forming a transparent electrode on a substrate such as
glass or a polymer film by a method such as vacuum deposition or
sputtering, and forming an organic material layer on the
transparent electrode. The organic material layer may include a
hole injection layer, a hole transport layer, an emitting layer, an
electron injection layer and/or an electron transport layer.
Subsequently, a second electrode is further formed on the organic
material layer. Afterward, the above-described adhesive film is
applied to a top surface of the organic electronic device on the
substrate to cover an entire surface of the organic electronic
device. Here, a method of applying the adhesive film is not
particularly limited, but may be heating or compressing a cover
substrate (e.g., glass or a polymer film) to which the
above-described adhesive layer of the adhesive film is previously
transfer-printed to a top surface of the organic electronic device
formed on the substrate. In this operation, for example, when the
adhesive film is transfer-printed on the cover substrate, the
above-described adhesive film may be transfer-printed on the cover
substrate using a vacuum press or vacuum laminator by applying heat
after a base or release film formed on the film is peeled off. In
this operation, when a curing reaction of the adhesive film is
performed in a certain range or more, cohesive strength or adhesive
strength of the adhesive film may be decreased, thereby controlling
a process temperature and a process time to approximately
100.degree. C. and approximately 5 minutes, respectively.
Similarly, even when the cover substrate on which the adhesive film
is transfer-printed is heat-compressed to the organic electronic
device, a vacuum press or vacuum laminator may be used. A
temperature condition for this operation may be set as described
above, and a process time may be within 10 minutes.
[0085] In addition, an additional curing process to the adhesive
film to which the organic electronic device is compressed may be
performed, and such a curing process (main curing) may be
performed, for example, in a heating chamber or UV chamber. A
curing condition in the main curing may be suitably selected in
consideration of stability of the organic electronic device.
[0086] However, the above-described forming process is merely an
example for encapsulating the organic electronic device, and thus a
sequence of or condition for the process may be freely changed. For
example, the sequence of the transfer-printing and compressing
processes may be changed in such a manner that the above-described
adhesive film is transfer-printed to the organic electronic device
on the substrate, followed by compressing the cover substrate. In
addition, after the protective layer is formed on the organic
electronic device, the adhesive film is applied and then cured
without the cover substrate.
[0087] Hereinafter, the present invention will be described in
further detail with reference to Examples according to the present
invention and Comparative Examples not according to the present
invention, but the scope of the present invention is not limited to
the following Examples.
Example 1
1. Preparation of Solution for First Sub-Adhesive Layer
[0088] 50 g of an epoxy resin (YD-128, Kukdo Chemical Co., Ltd.)
and 50 g of a phenoxy resin (YP-50, Tohto Kasei Co., Ltd.) were put
into a reactor, and diluted with 100 g of methylethylketone. 1 g of
an imidazole curing agent (2MA.OK, Shikoku Chemicals Co., Ltd.) was
added thereto, and the resulting solution was homogenized.
2. Preparation of Solution for Second Sub-Adhesive Layer
[0089] A moisture adsorbent solution was prepared by adding 10 g of
MgO at a concentration of 20 weight % as a moisture adsorbent to
methylethylketone, and milled for 24 hours by ball-milling. In
addition, separately, 60 g of an epoxy resin (YD-128, Kukdo
Chemical Co., Ltd.) and 40 g of a phenoxy resin (YP-50, Tohto Kasei
Co., Ltd.) were put into a reactor, and diluted with 100 g of
methylethylketone. Afterward, 1 g of an imidazole curing agent
(2MA.OK, Shikoku Chemicals Co., Ltd.) was added thereto, and the
resulting solution was homogenized. The previously prepared
moisture adsorbent solution was put into the homogenized solution,
and stirred at high speed for 1 hour, thereby preparing a solution
for a second sub-adhesive layer.
3. Formation of Adhesive Film
[0090] A first sub-adhesive layer having a thickness of 15 .mu.m
was formed by applying the above-prepared solution for a first
sub-adhesive layer to a release surface of release PET using a
comma coater, and drying the resulting surface in a drier at
130.degree. C. for 3 minutes.
[0091] A second sub-adhesive layer having a thickness of 30 .mu.m
was formed by applying the above-prepared solution for a second
sub-adhesive layer to a release surface of release PET using a
comma coater, and drying the resulting surface in a drier at
130.degree. C. for 3 minutes.
[0092] The first and second sub-adhesive layers are assembled,
thereby forming a multilayered adhesive film.
Example 2
[0093] An adhesive film having a monolayered structure having a
thickness of 45 .mu.m was formed only using the solution for a
second sub-adhesive layer in Example 1.
Example 3
[0094] A multilayered adhesive film was formed as described in
Example 1, except that the solutions for first and second
sub-adhesive layers were prepared as to be described below.
[0095] 1. Preparation of Solution for First Sub-Adhesive Layer
[0096] 25 g of an epoxy resin (YD-128, Kukdo Chemical Co., Ltd.),
35 g of epoxy resin (YD-014, Kukdo Chemical Co., Ltd.) and 40 g of
a phenoxy resin (YP-50, Tohto Kasei Co., Ltd.) were put into a
reactor, and diluted with 100 g of methylethylketone. 1 g of an
imidazole curing agent (2MA.OK, Shikoku Chemicals Co., Ltd.) was
added thereto, and the resulting solution was homogenized.
[0097] 2. Preparation of Solution for Second Sub-Adhesive layer
[0098] A moisture adsorbent solution was prepared by adding 10 g of
MgO at a concentration of 20 weight % as a moisture adsorbent to
methylethylketone, and milled for 24 hours by ball-milling. In
addition, separately, 55 g of an epoxy resin (YD-128, Kukdo
Chemical Co., Ltd.) and 45 g of a phenoxy resin (YP-50, Tohto Kasei
Co., Ltd.) were put into a reactor, and diluted with 100 g of
methylethylketone. Afterward, 1 g of an imidazole curing agent
(2MA.OK, Shikoku Chemicals Co., Ltd.) was added thereto, and the
resulting solution was homogenized. The previously prepared
moisture adsorbent solution was put into the homogenized solution,
and stirred at high speed for 1 hour, thereby preparing a solution
for a second sub-adhesive layer.
Example 4
[0099] A multilayered adhesive film was formed as described in
Example 1, except that the solutions for first and second
sub-adhesive layers were prepared as to be described below.
[0100] 1. Preparation of Solution for First Sub-Adhesive Layer
[0101] 50 g of an epoxy resin (YD-128, Kukdo Chemical Co., Ltd.)
and 50 g of a phenoxy resin (YP-50, Tohto Kasei Co., Ltd.) were put
into a reactor, and diluted with 100 g of methylethylketone. 1 g of
an imidazole curing agent (2MA.OK, Shikoku Chemicals Co., Ltd.) was
added thereto, and the resulting solution was homogenized.
Subsequently, 3 g of nano silica (Aerosil R972, Evonik Degussa) was
uniformly dispersed.
[0102] 2. Preparation of Solution for Second Sub-Adhesive layer
[0103] A moisture adsorbent solution was prepared by adding 10 g of
MgO at a concentration of 20 weight % as a moisture adsorbent to
methylethylketone, and milled for 24 hours by ball-milling. In
addition, separately, 50 g of an epoxy resin (YD-128, Kukdo
Chemical Co., Ltd.) and 50 g of a phenoxy resin (YP-50, Tohto Kasei
Co., Ltd.) were put into a reactor, and diluted with 100 g of
methylethylketone. Afterward, 1 g of an imidazole curing agent
(2MA.OK, Shikoku Chemicals Co., Ltd.) was added thereto, and the
resulting solution was homogenized. The previously prepared
moisture adsorbent solution was put into the homogenized solution,
and stirred at high speed for 1 hour, thereby preparing a solution
for a second sub-adhesive layer.
Comparative Example 1
[0104] A multilayered adhesive film was formed as described in
Example 1, except that the content of the phenoxy resin (YP-50,
Tohto Kasei Co., Ltd.) used in the solution for a first
sub-adhesive layer in Example 1 was changed to 30 g.
Comparative Example 2
[0105] An adhesive film having a monolayered structure having a
thickness of 45 .mu.m was formed as described in Example 2, except
that the epoxy and phenoxy resins used in the solution for a second
sub-adhesive layer in Example 2 were substituted with 20 g of an
epoxy resin (YD-128, Kukdo Chemical Co., Ltd.) and 80 g of a
phenoxy resin (YP-50, Tohto Kasei Co., Ltd.).
Comparative Example 3
[0106] An adhesive film having a monolayered structure having a
thickness of 45 .mu.m was formed as described in Example 2, except
that the epoxy and phenoxy resins used in the solution for a second
sub-adhesive layer in Example 2 were substituted with 80 g of an
epoxy resin (YD-128, Kukdo Chemical Co., Ltd.) and 20 g of a
phenoxy resin (YP-50, Tohto Kasei Co., Ltd.).
Comparative Example 4
[0107] A multilayered adhesive film was formed as described in
Example 1, except that the solutions for first and second
sub-adhesive layers were prepared as to be described below.
[0108] 1. Preparation of Solution for First Sub-Adhesive Layer
[0109] 50 g of an epoxy resin (YD-128, Kukdo Chemical Co., Ltd.)
and 30 g of a phenoxy resin (YP-50, Tohto Kasei Co., Ltd.) were put
into a reactor, and diluted with 100 g of methylethylketone. 1 g of
an imidazole curing agent (2MA.OK, Shikoku Chemicals Co., Ltd.) was
added thereto, and the resulting solution was homogenized.
[0110] 2. Preparation of Solution for Second Sub-Adhesive layer
[0111] A moisture adsorbent solution was prepared by adding 10 g of
MgO at a concentration of 20 weight % as a moisture adsorbent to
methylethylketone, and milled for 24 hours by ball-milling. In
addition, separately, 60 g of an epoxy resin (YD-128, Kukdo
Chemical Co., Ltd.) and 40 g of a phenoxy resin (YP-50, Tohto Kasei
Co., Ltd.) were put into a reactor, and diluted with 100 g of
methylethylketone. Afterward, 1 g of an imidazole curing agent
(2MA.OK, Shikoku Chemicals Co., Ltd.) was added thereto, and the
resulting solution was homogenized. The previously prepared
moisture adsorbent solution was put into the homogenized solution,
and stirred at high speed for 1 hour, thereby preparing a solution
for a second sub-adhesive layer.
Comparative Example 5
[0112] A multilayered adhesive film was formed as described in
Example 1, except that the content of MgO was changed to 70 g in
the preparation of a moisture adsorbent solution added to the
solution for a second sub-adhesive layer in Example 1.
Experimental Example 1
Measurement of Viscosity
[0113] Viscosities according to a temperature of the adhesive
layers of the adhesive films in Examples 1 to 4 and Comparative
Examples 1 to 5 were measured using an ARES, and the viscosities at
room temperature and 80.degree. C. are shown in Table 1.
TABLE-US-00001 TABLE 1 Viscosity at Increasing Viscosity at Room
Temperature Temperature (Pa s, 25.degree. C.) (Pa s, 80.degree. C.)
Example 1 3.8 .times. 10.sup.6 2367 Example 2 4.2 .times. 10.sup.6
2385 Example 3 6.9 .times. 10.sup.6 3250 Example 4 1.1 .times.
10.sup.7 6790 Comparative 1.2 .times. 10.sup.6 1825 Example 1
Comparative 1.9 .times. 10.sup.8 1.2 .times. 10.sup.6 Example 2
Comparative 7.8 .times. 10.sup.4 890 Example 3 Comparative 9.8
.times. 10.sup.5 1439 Example 4 Comparative 8.8 .times. 10.sup.6
5932 Example 5
Experimental Example 2
Measurement of Difference in Viscosity Between Layers
[0114] Viscosities of two sub-adhesive layers of the adhesive layer
of the adhesive film in each of Examples 1, 3 and 4 and Comparative
Examples 1, 4 and 5 were measured using an ARES, and viscosities at
80.degree. C. and a difference in viscosity (between the layers)
are shown in Table 2.
TABLE-US-00002 TABLE 2 Viscosity Difference in Viscosity of
1.sup.st Sub- of 2.sup.nd Sub- Viscosity between Adhesive Layer
Adhesive Layer Layers (Pa s, 80.degree. C.) (Pa s, 80.degree. C.)
(Pa s, 80.degree. C.) Example 1 2365 2371 6 Example 3 2386 2381 5
Example 4 3265 3248 17 Comparative 1642 2371 729 Example 1
Comparative 1642 890 752 Example 4 Comparative 2365 4009 1644
Example 5
Experimental Example 3
Measurement of Leaking Degree in Lamination
[0115] A degree of leaking the adhesive layer of the adhesive film
from an early end of the adhesive film of each of Examples 1 to 4
and Comparative Examples 1 to 5 was measured using a microscope at
a lamination temperature of 80.degree. C., and the results are
shown in Table 3.
TABLE-US-00003 TABLE 3 Release Degree (.mu.m) Difference in
1.sup.st Sub-Adhesive 2.sup.nd Sub-Adhesive Release Degree Layer
(A) Layer (B) |A - B| Example 1 510 500 10 Example 2 -- 485 --
Example 3 480 480 0 Example 4 320 320 0 Comparative 840 530 310
Example 1 Comparative -- 30 -- Example 2 Comparative -- 1500 --
Example 3 Comparative 850 1480 630 Example 4 Comparative 480 40 440
Example 5
Experimental Example 4
Confirmation of Moisture Blocking Property
[0116] A calcium test was executed to investigate moisture blocking
properties of the adhesive film in each of Examples 1 to 4 and
Comparative Examples 1 to 5. Particularly, 9 spots of calcium (Ca)
were deposited to a size of 5 mm.times.5 mm and a thickness of 100
nm on a glass substrate having a size of 100 mm.times.100 mm, a
cover glass to which the adhesive film of each of Examples 1 to 4
and Comparative Examples 1 to 5 is transfer-printed was
heat-compressed to each calcium-deposited spot at 80.degree. C. for
1 minute using a vacuum press. Afterward, the resulting product was
cured in a high-temperature drier at 100.degree. C. for 3 hours,
and an encapsulated calcium specimen was cut into a size of 11
mm.times.11 mm. The obtained specimens were left in an environment
including a temperature of 85.degree. C. and an R.H. of 85% in a
constant temperature and constant humidity chamber, and a point at
which calcium starts turning transparent by an oxidation reaction
due to penetration of moisture was measured. The results are shown
in Table 4.
TABLE-US-00004 TABLE 4 Time to Start Transparency(h) Example 1 210
Example 2 210 Example 3 210 Example 4 220 Comparative 190 Example 1
Comparative Not measured due to lamination failure Example 2
Comparative 160 Example 3 Comparative 100 Example 4 Comparative Not
measured due to failure of Example 5 aggravation of leakage
Experimental Example 5
Measurement of Bubbling Degree
[0117] A degree of remaining bubbles in lamination was observed
using a microscope when a 3-inch organic light-emitting panel was
formed using the adhesive film in each of Examples 1 to 4 and
Comparative Examples 1 to 5, and the results are shown in Table
5.
TABLE-US-00005 TABLE 5 Degree of Remaining Bubbles Example 1
.circleincircle. Example 2 .largecircle. Example 3 .circleincircle.
Example 5 .largecircle. Comparative .largecircle. Example 1
Comparative X Example 2 Comparative X Example 3 Comparative X
Example 4 Comparative X Example 5 *.circleincircle.: no bubbles,
.largecircle.: a small amount of bubbles having a diameter of 100
.mu.m or less, and X: presence of bubbles having 1 mm or more
[0118] In addition, in the formation of an organic light-emitting
panel using the adhesive film in each of Example 1 and Comparative
Examples 1 and 2, an optical microscopic image observing a degree
of remaining bubbles after lamination is shown in FIGS. 5 to 7.
Referring to FIG. 5, it can be confirmed that the adhesive film was
laminated without bubbles. However, it was confirmed that a large
amount of bubbles were captured, and thus a failure was generated
in Comparative Example 4, and a lamination failure was generated in
Comparative Example 2.
[0119] As seen from the above, in the adhesive films in Examples 1
to 4 according to exemplary embodiments of the present invention, a
difference between viscosities at room temperature and increasing
temperature and viscosities between layers in a multilayered
structure was controlled in a specific range in an uncured state,
thereby reducing the occurrence of failures and effectively
encapsulating the organic electronic device from moisture when an
encapsulated product of an organic electronic device was
manufactured. However, it can be confirmed that the organic
electronic device was not effectively encapsulated when viscosity
was not properly controlled as shown in Comparative Example(s).
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